Began documenting API

- Added PhlySimplePage as a dependency, to allow an easy way to add the
  documentation end point.
- Created a new "documentation" child route that specifies
  PhlySimplePage and a template.
  - Made all routes except "user" literal; there should be a 1:1
    URL/resource relationship.
  - Documentation page is written in markdown.
  - Added listener to PhlySimplePage to mark this particular view model
    terminal, and set the Content-Type to text/x-markdown
- Added a Link header to all API end points that points a "describedby"
  relation at the documentation page.
Fixed variable name typo
Various fixes

- php 5.4 web server uses file extensions; cannot test a ".md" in the
  route. Removed the extension.
- Fixed the logic for creating the Link header
- Added view configuration for the documentation file